Question: Can I still use a FSBP beltpack when it is connected to the single charging unit  (400115Z)  Can I need to power-up theFS-BP directly without using the AA battery.
Answer: No.  FS-BP has to use 4 x AA-format batteries to power-up.  When the charging PSU (400115Z) unit is plugged into the beltpack, it will automatically shut off for charging.
Battery Recharger ConnectorTheFreeSpeak beltpack features an internal battery charger to charge the fourAA-format NiMH batteries used to power the unit. The recharger circuit includesa thermistor that senses the temperature of the battery pack to preventovercharging. To use this internal recharger, plug in the small barrelconnector on the supplied universal power supply into the beltpack connector,and then plug the supply into the local AC current. The beltpack willautomatically shut off when the charging PSU is plugged into it. While it ischarging, the beltpack cannot be turned on. The unit can only be turned on whenthe charging PSU is disconnected. A full charge takes approximately 3 to 4hours depending on the battery capacity. After this time, the charger willmaintain a trickle charge to keep the beltpack fully charged. FreeSpeakbeltpack usage time is dependent upon the batteries used. Some batteriesrequire more charge/discharge cycles than others to reach their rated capacity.
Caution:Do not put battery packs containing alkaline batteries into a recharger, orrecharge them in the beltpack. Serious damage or injury could result.